A three-dimensional capacitive non-touching detection system generates a quasi-static electric field wherein disturbances in that field that are caused by an object entering the field are evaluated. The evaluation allows for a determination of a three-dimensional location of the object, such as a finger of a user, and to track its position to further determine whether a gesture from a predefined pool of gestures has been performed. Such a system can also operate as a three-dimensional touchless mouse or control any kind of suitable operations without requiring a touch. The system usually uses a transmitting electrode receiving an alternating signal such as a sinusoidal or square wave signal, for example, having a frequency of 40-250 kHz, to generate the quasi-static alternating electric field. Contrary to, for example, mutual or self capacitance measurements, during measurement the transmitting electrode is supplied permanently with the generator signal and disturbances in the generated field are measured while the field is permanently upheld. The system does not evaluate single pulses, voltages generated by single or multiple pulses and associated charge changes of the sensor electrodes as it is common in capacitance measurement systems, for example, a capacitive voltage divider or a charge time measurement unit used for mutual or self capacitance measurements. In some embodiments, a plurality of receiving electrodes are arranged above a transmitting electrode, for example in a frame-like fashion within a plane to evaluate the quasi-static electric field generated by the transmitting electrode, and from received signals a three-dimensional position of an object can be reconstructed within an integrated circuit device through signal processing. In other embodiments, the same electrodes are used for transmitting and receiving and while still the same electric field is generated, the evaluation measures a load on each transmitter/receiver electrode caused by a disturbance in the electric field.
An example of such a device is the “GestiC®” integrated circuit, also known as MGC3130 manufactured by the assignee of this application. This device is a highly sensitive capacitive sensing technology that can be used for three-dimensional touch-less gesture detection and tracking using a quasi-static alternating electric near field, for example around 40-250 kHz.